Systems and methods for energy storage using phosphorescence and waveguides

ABSTRACT

Provided herein are systems and methods for storing energy. A photon battery assembly may comprise a light source, phosphorescent material, a photovoltaic cell, and a waveguide. The phosphorescent material can absorb optical energy at a first wavelength from the light source and, after a time delay, emit optical energy at a second wavelength after a time delay. The photovoltaic cell may absorb the optical energy at the second wavelength and generate electrical power. In some instances, a first waveguide may be configured to direct the optical energy at the first wavelength from the light source to the phosphorescent material and/or a second waveguide may be configured to direct the optical energy at the second wavelength from the phosphorescent material to the photovoltaic cell.

CROSS-REFERENCE

This application is a continuation of International Patent ApplicationNo. PCT/US19/020592, filed Mar. 4, 2019, which claims benefit of U.S.Provisional Application No. 62/638,646, filed Mar. 5, 2018, each ofwhich applications is entirely incorporated herein by reference for allpurposes.

BACKGROUND

Especially in an age where so many activities and functions depend on acontinuous supply of power, lapses or interruptions in the provision ofpower may lead to highly undesirable results. These recent years haveseen a fast-growing market for readily accessible power, such as inbatteries, supercapacitors, fuel cells, and other energy storagedevices. However, such energy storage devices are often limited in manyaspects. For example, they may be volatile or unstable under certainoperating conditions (e.g., temperature, pressure) and becomeineffective or pose a safety hazard. In some cases, an energy storagedevice may itself be consumed during one or more cycles of converting orstoring energy and thus have limited lifetime. In some cases, a rate ofcharging may be too slow to effectively support or satisfy a rate ofconsumption of power.

SUMMARY

Recognized herein is a need for reliable systems and methods for energystorage. The systems and methods for energy storage disclosed herein mayprovide superior charging rates to those of conventional chemicalbatteries, for example, on the order of 100 times faster or more. Thesystems and methods disclosed herein may provide superior lifetimes tothose of conventional chemical batteries, for example, on the order of10 times more recharge cycles or more. The systems and methods disclosedherein may be portable. The systems and methods disclosed herein may bestable and effective in relatively cold operating temperatureconditions.

The systems and methods disclosed herein may use phosphorescent materialto store energy over a finite duration of time. For example, thephosphorescent material may store and/or convert energy with substantialtime delay. The systems and methods disclosed herein may use lightsources to provide an initial source of energy in the form of opticalenergy. The light sources can be artificial light sources, such as lightemitting diodes (LEDs). The systems and methods disclosed herein may usephotovoltaic cells to generate electrical power from optical energy. Asystem for energy storage may comprise a light source, a phosphorescentmaterial, a photovoltaic cell, and a waveguide to direct waves betweenthe light source and the phosphorescent material and/or between thephotovoltaic cell and the phosphorescent material.

In an aspect, provided is a system for storing energy, comprising: alight source configured to emit optical energy at a first wavelengthfrom a surface of the light source; a phosphorescent material configuredto (i) absorb the optical energy at the first wavelength, and (ii) at arate slower than a rate of absorption, emit optical energy at a secondwavelength, wherein the second wavelength is greater than the firstwavelength; a photovoltaic cell adjacent to the phosphorescent material,wherein the photovoltaic cell is configured to (i) absorb optical energyat the second wavelength, and (ii) generate electrical power fromoptical energy; and a waveguide adjacent to the phosphorescent material,wherein the waveguide is configured to (i) direct the optical energy atthe first wavelength from the light source to the phosphorescentmaterial or (ii) direct the optical energy at the second wavelength fromthe phosphorescent material to the photovoltaic cell.

In some embodiments, the waveguide is configured to direct the opticalenergy at the first wavelength from the light source to thephosphorescent material and wherein the system comprises a secondwaveguide configured to direct the optical energy at the secondwavelength from the phosphorescent material to the photovoltaic cell. Insome embodiments, the second waveguide and the phosphorescent materialare concentric.

In some embodiments, the waveguide is configured to direct the opticalenergy at the first wavelength from the light source to thephosphorescent material, and wherein the waveguide is adjacent to thelight source. In some embodiments, the waveguide is in contact with thelight source.

In some embodiments, the waveguide is configured to direct the opticalenergy at the second wavelength from the phosphorescent material to thephotovoltaic cell, and wherein the waveguide is adjacent to thephotovoltaic cell. In some embodiments, the waveguide is in contact withthe photovoltaic cell.

In some embodiments, the waveguide comprises one or more reflectivesurfaces, wherein the reflective surfaces are configured to (i) directthe optical energy at the first wavelength from the light source to thephosphorescent material or (ii) direct the optical energy at the secondwavelength from the phosphorescent material to the photovoltaic cell. Insome embodiments, the waveguide comprises a plurality of reflectivesurfaces having increasingly large reflective surfaces along an opticalpath within the waveguide, such that a first set of waves from the lightsource are configured to be reflected at a first reflective surface ofthe plurality of reflective surfaces for excitation of a first volume ofphosphorescent material, and a second set of waves from the light sourceare configured to be reflected at a second reflective surface of theplurality of reflective surfaces for excitation of a second volume ofphosphorescent material, wherein the second volume of phosphorescentmaterial is disposed at a greater distance from the light source thanthe first volume of phosphorescent material.

In some embodiments, the light source is a light-emitting diode (LED).

In some embodiments, a rechargeable battery is electrically coupled tothe light source and the photovoltaic cell, and wherein at least part ofthe electrical power generated by the photovoltaic cell charges therechargeable battery, and wherein at least part of electrical powerdischarged by the rechargeable battery powers the light source.

In some embodiments, the phosphorescent material comprises strontiumaluminate and europium. In some embodiments, the phosphorescent materialcomprises dysprosium.

In some embodiments, the phosphorescent material comprises grains havinga particle size of less than about 5 micrometers.

In some embodiments, the phosphorescent material comprises grains havinga particle size of less than about 20 nanometers.

In some embodiments, the light source is adjacent to and in contact withthe waveguide.

In some embodiments, the light source is not in contact with thewaveguide and the phosphorescent material. In some embodiments, thelight source is located remote from the waveguide and the phosphorescentmaterial, wherein the light source is in optical communication with thewaveguide.

In some embodiments, the system further comprises a coating on thewaveguide, wherein the coating is in optical communication with thewaveguide and the phosphorescent material, wherein the coating comprisesan optical filter. In some embodiments, the optical filter is a dichroicelement. In some embodiments, the optical filter is configured totransmit waves having the first wavelength from the waveguide to thephosphorescent material and reflect waves having the second wavelengthfrom the phosphorescent material back to the phosphorescent material. Insome embodiments, the coating is in contact with the waveguide and thephosphorescent material.

In another aspect, provided is a method for storing energy, comprising:(a) emitting optical energy at a first wavelength from a surface of alight source; (b) directing the optical energy at the first wavelength,via a first waveguide, to a phosphorescent material; (c) at a rateslower than a rate of absorption of the optical energy at the firstwavelength, emitting, by the phosphorescent material, optical energy ata second wavelength, wherein the second wavelength is greater than thefirst wavelength; (d) directing the optical energy at the secondwavelength, via a second waveguide, to a photovoltaic cell, wherein thesurface of the photovoltaic cell is adjacent to the phosphor; and (e)generating electrical power from the optical energy at the secondwavelength.

In some embodiments, the second waveguide and the phosphorescentmaterial are concentric.

In some embodiments, the first waveguide is adjacent to the lightsource.

In some embodiments, the second waveguide is adjacent to thephotovoltaic cell.

In some embodiments, the first waveguide comprises one or morereflective surfaces, wherein the reflective surfaces are configured todirect the optical energy at the first wavelength from the light sourceto the phosphorescent material. In some embodiments, the first waveguidecomprises a plurality of reflective surfaces having increasingly largereflective surfaces along an optical path within the first waveguide,such that a first set of waves from the light source are configured tobe reflected at a first reflective surface of the plurality ofreflective surfaces for excitation of a first volume of phosphorescentmaterial, and a second set of waves from the light source are configuredto be reflected at a second reflective surface of the plurality ofreflective surfaces for excitation of a second volume of phosphorescentmaterial, wherein the second volume of phosphorescent material isdisposed at a greater distance from the light source than the firstvolume.

In some embodiments, the light source is a light-emitting diode (LED).

In some embodiments, a rechargeable battery is electrically coupled tothe light source and the photovoltaic cell, and wherein at least part ofthe electrical power generated by the photovoltaic cell charges therechargeable battery, and wherein at least part of electrical powerdischarged by the rechargeable battery powers the light source.

In some embodiments, the phosphorescent material comprises strontiumaluminate and europium. In some embodiments, the phosphorescent materialcomprises dysprosium.

In some embodiments, the phosphorescent material comprises grains havinga particle size of less than about 5 micrometers.

In some embodiments, the phosphorescent material comprises grains havinga particle size of less than about 20 nanometers.

In some embodiments, the light source is in contact with the firstwaveguide.

In some embodiments, the light source is not in contact with the firstwaveguide and the phosphorescent material. In some embodiments, thelight source is located remote from the first waveguide and thephosphorescent material, wherein the light source is in opticalcommunication with the first waveguide.

In some embodiments, the first waveguide comprises a coating on thefirst waveguide, wherein the coating is in optical communication withthe first waveguide and the phosphorescent material, wherein the coatingcomprises an optical filter. In some embodiments, the optical filter isa dichroic element. In some embodiments, the optical filter isconfigured to transmit waves having the first wavelength from the firstwaveguide to the phosphorescent material and reflect waves having thesecond wavelength from the phosphorescent material back to thephosphorescent material. In some embodiments, the coating is in contactwith the waveguide and the phosphorescent material.

In another aspect, provided is a method for wireless charging,comprising: (a) providing a battery assembly comprising: aphosphorescent material configured to (i) absorb optical energy at afirst wavelength, and (ii) at a rate slower than a rate of absorption,emit optical energy at a second wavelength, wherein the secondwavelength is greater than the first wavelength; a photovoltaic celladjacent to the phosphorescent material, wherein the photovoltaic cellis configured to (i) absorb optical energy at the second wavelength, and(ii) generate electrical power from optical energy; and a waveguideadjacent to the phosphorescent material, wherein the waveguide isconfigured to (i) direct the optical energy at the first wavelength froma light source to the phosphorescent material or (ii) direct the opticalenergy at the second wavelength from the phosphorescent material to thephotovoltaic cell; and (b) providing optical energy at the firstwavelength from the light source to the waveguide, wherein the lightsource is not in contact with the waveguide and the phosphorescentmaterial, and wherein the light source is in optical communication withthe waveguide. emitting optical energy at a first wavelength from asurface of a light source, thereby charging the battery assembly.

Another aspect of the present disclosure provides a non-transitorycomputer readable medium comprising machine executable code that, uponexecution by one or more computer processors, implements any of themethods above or elsewhere herein.

Another aspect of the present disclosure provides a system comprisingone or more computer processors and computer memory coupled thereto. Thecomputer memory comprises machine executable code that, upon executionby the one or more computer processors, implements any of the methodsabove or elsewhere herein.

Additional aspects and advantages of the present disclosure will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein only illustrative embodiments of thepresent disclosure are shown and described. As will be realized, thepresent disclosure is capable of other and different embodiments, andits several details are capable of modifications in various obviousrespects, all without departing from the disclosure. Accordingly, thedrawings and description are to be regarded as illustrative in nature,and not as restrictive.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings (also “Figure” and “FIG.” herein) of which:

FIG. 1 shows an exemplary photon battery assembly.

FIG. 2 shows a photon battery in communication with an electrical load.

FIG. 3 shows an exemplary photon battery assembly in application.

FIG. 4A illustrates a photon battery assembly with a waveguide.

FIG. 4B illustrates a photon battery assembly with a coating comprisingan optical filter.

FIG. 5 illustrates another photon battery assembly with a waveguide.

FIG. 6 illustrates another photon battery assembly with waveguides.

FIG. 7 shows a stack of a plurality of photon battery assemblies.

FIG. 8 shows an exploded view of another configuration for a photonbattery assembly stack with hollow core waveguides.

FIG. 9 illustrates a partial cross-sectional side view of the photonbattery assembly stack of FIG. 8.

FIG. 10 illustrates a method of storing energy in a photon battery.

FIG. 11 shows a computer system configured to implement systems andmethods of the present disclosure.

DETAILED DESCRIPTION

While various embodiments of the invention have been shown and describedherein, it will be obvious to those skilled in the art that suchembodiments are provided by way of example only. Numerous variations,changes, and substitutions may occur to those skilled in the art withoutdeparting from the invention. It should be understood that variousalternatives to the embodiments of the invention described herein may beemployed.

Provided herein are systems and methods for energy storage. The systemsand methods disclosed herein may use phosphorescent material to storeenergy over a significant duration of time, such as by making use of thetime-delayed re-emission properties of phosphorescent material. Forexample, the phosphorescent material may store and/or convert energywith substantial time delay. A light source can provide an initialsource of energy to the phosphorescent material in the form of opticalenergy. For example, the phosphorescent material may absorb opticalenergy from the light source at a first wavelength, and after a timedelay, emit optical energy at a second wavelength. The light source canbe an artificial light source, such as a light emitting diode (LED). Aphotovoltaic cell can generate electrical power from optical energy,such as from optical energy at the second wavelength that is emitted bythe phosphorescent material. A waveguide may direct waves, such as theoptical energy from the light source at the first wavelength between thelight source and the phosphorescent material and/or the optical energyat the second wavelength between the phosphorescent material and thephotovoltaic cell. Such waveguides may increase energy density andcompactness of the energy storage system. Beneficially, such waveguidemay greatly increase efficiency of the time-delayed optical energytransfer between the phosphorescent material and the light source andthe photovoltaic cell, as well as facilitate efficient use of theavailable phosphorescent material.

The systems and methods for energy storage disclosed herein may providesuperior charging rates to those of conventional chemical batteries, forexample, on the order of 100 times faster or more. The systems andmethods disclosed herein may provide superior lifetimes to those ofconventional chemical batteries, for example, on the order of 10 timesmore recharge cycles or more. The systems and methods disclosed hereinmay be portable. The systems and methods disclosed herein may be stableand effective in relatively cold operating temperature conditions.

Reference will now be made to the figures. It will be appreciated thatthe figures and features therein are not necessarily drawn to scale.

FIG. 1 shows an exemplary photon battery assembly. A photon batteryassembly 100 can comprise a light source 101, a phosphorescent material102, and a photovoltaic cell 103. The phosphorescent material may beadjacent to both the light source and the photovoltaic cell. Forexample, the phosphorescent material can be sandwiched by the lightsource and the photovoltaic cell. The phosphorescent material can bebetween the light source and the photovoltaic cell. While FIG. 1 showsthe light source, phosphorescent material, and photovoltaic cell as avertical stack, the configuration is not limited as such. For example,the light source, phosphorescent material, and photovoltaic cell can behorizontally stacked or concentrically stacked. The light source and thephotovoltaic cell may or may not be adjacent to each other. In someinstances, the phosphorescent material can be adjacent to alight-emitting surface of the light source. In some instances, thephosphorescent material can be adjacent to a light-absorbing surface ofthe photovoltaic cell.

Regardless of contact between the phosphorescent material 102 and lightsource 101, the phosphorescent material and the light source may be inoptical communication. For example, as described elsewhere herein, thephosphorescent material and the light source may be in opticalcommunication via a waveguide. Regardless of contact between thephosphorescent material and photovoltaic cell 103, the phosphorescentmaterial and the photovoltaic cell may be in optical communication. Forexample, as described elsewhere herein, the phosphorescent material andthe photovoltaic cell may be in optical communication via a waveguide.In some instances, the same waveguide may be configured to facilitateoptical communication between the phosphorescent material and thephotovoltaic cell and between the phosphorescent material and the lightsource.

The phosphorescent material 102 may or may not be contacting the lightsource 101. If the phosphorescent material and the light source are incontact, the phosphorescent material can interface a light-emittingsurface of the light source. The phosphorescent material and the lightsource can be coupled or fastened together at the interface, such as viaa fastening mechanism. In some instances, a support carrying the lightsource and/or a support carrying the phosphorescent material may becoupled or fastened together at the interface. Examples of fasteningmechanisms may include, but are not limited to, form-fitting pairs,hooks and loops, latches, staples, clips, clamps, prongs, rings, brads,rubber bands, rivets, grommets, pins, ties, snaps, velcro, adhesives,tapes, a combination thereof, or any other types of fasteningmechanisms. In some instances, the phosphorescent material may haveadhesive and/or cohesive properties and adhere to the light sourcewithout an independent fastening mechanism. For example, thephosphorescent material may be painted or coated on the light-emittingsurface of the light source. In some instances, the phosphorescentmaterial may be coated onto primary, secondary, and/or tertiary opticsof the light source. In some instances, the phosphorescent material maybe coated onto other optical elements of the light source. Thephosphorescent material and the light source can be permanently ordetachably fastened together. For example, the phosphorescent materialand the light source can be disassembled from and reassembled into thephoton battery assembly 100 without damage (or with minimal damage) tothe phosphorescent material and/or the light source. Alternatively,while in contact, the phosphorescent material and the light source maynot be fastened together.

If the phosphorescent material 102 and the light source 101 are not incontact, the phosphorescent material can otherwise be in opticalcommunication with a light-emitting surface of the light source, such asvia a waveguide. For example, the phosphorescent material can bepositioned in an optical path of light emitted by the light-emittingsurface of the light source. In some instances, there can be an air gapbetween the phosphorescent material and the light source. In someinstances, there can be another intermediary layer between thephosphorescent material and the light source. The intermediary layer canbe air or other fluid. The intermediary layer can be a light guide oranother layer of optical elements (e.g., lens, reflector, diffusor, beamsplitter, etc.). In some instances, there can be a plurality ofintermediary layers between the phosphorescent material and the lightsource.

The phosphorescent material 102 may or may not be contacting thephotovoltaic cell 103. If the phosphorescent material and thephotovoltaic cell are in contact, the phosphorescent material caninterface a light-absorbing surface of the photovoltaic cell. Thephosphorescent material and the photovoltaic cell can be coupled orfastened together at the interface, such as via a fastening mechanism.In some instances, a support carrying the photovoltaic cell and/or asupport carrying the phosphorescent material may be coupled or fastenedtogether at the interface. In some instances, the phosphorescentmaterial may have adhesive properties and adhere to the photovoltaiccell without an independent fastening mechanism. For example, thephosphorescent material may be painted or coated on the light-absorbingsurface of the photovoltaic cell. In some instances, the phosphorescentmaterial may be coated onto primary, secondary, and/or tertiary opticsof the photovoltaic cell. In some instances, the phosphorescent materialmay be coated onto other optical elements of the photovoltaic cell. Thephosphorescent material and the photovoltaic cell can be permanently ordetachably fastened together. For example, the phosphorescent materialand the photovoltaic cell can be disassembled from and reassembled intothe photon battery assembly 100 without damage (or with minimal damage)to the phosphorescent material and/or the photovoltaic cell.Alternatively, while in contact, the phosphorescent material and thephotovoltaic cell may not be fastened together.

If the phosphorescent material 102 and the photovoltaic cell 103 are notin contact, the phosphorescent material can otherwise be in opticalcommunication with a light-absorbing surface of the photovoltaic cell.For example, the light-absorbing surface of the photovoltaic cell can bepositioned in an optical path of light emitted by the phosphorescentmaterial. In some instances, there can be an air gap between thephosphorescent material and the photovoltaic cell. In some instances,there can be another intermediary layer between the phosphorescentmaterial and the photovoltaic cell. The intermediary layer can be air orother fluid. The intermediary layer can be a light guide, lightconcentrator, or another layer of optical elements (e.g., lens,reflector, diffusor, beam splitter, etc.). In some instances, there canbe a plurality of intermediary layers between the phosphorescentmaterial and the photovoltaic cell.

In some instances, the photon battery assembly 100 can be assembled ordisassembled, such as into the light source 101, phosphorescent material102, or the photovoltaic cell 103 independently, or intosub-combinations thereof. In some instances, the photon battery assemblycan be assembled or disassembled without damage to the different partsor with minimal damage to the different parts.

In some instances, the photon battery assembly 100 can be housed in ashell, outer casing, or other housing. The photon battery assembly 100,and/or shell thereof can be portable. For example, the photon batteryassembly can have a maximum dimension of at most about 1 meter (m), 90centimeters (cm), 80 cm, 70 cm, 60 cm, 50 cm, 45 cm, 40 cm, 35 cm, 30cm, 25 cm, 20 cm, 15 cm, 10 cm, 9 cm, 8 cm, 7 cm, 6 cm, 5 cm, orsmaller. A maximum dimension of the photon battery assembly may be adimension of the photon battery assembly (e.g., length, width, height,depth, diameter, etc.) that is greater than the other dimensions of thephoton battery assembly. Alternatively, the photon battery assembly mayhave greater maximum dimensions. For example, a photon battery assemblyhaving a higher energy storage capacity can have larger dimensions andmay not be portable.

The light source 101 can be an artificial light source, such as a lightemitting diode (LED) or other light emitting device. For example, thelight source can be a laser or a lamp. The light source can be aplurality of light emitting devices (e.g., a plurality of LEDs). In someinstances, the light source can be arranged as one LED. In someinstances, the light source can be arranged as rows or columns ofmultiple LEDs. The light source can be arranged as arrays or grids ofmultiple columns, rows, or other axes of LEDs. The light source can be acombination of different light emitting devices. A light emittingsurface of the light source can be planar or non-planar. A lightemitting surface of the light source can be substantially flat,substantially curved, or form another shape.

The light source can be supported by rigid and/or flexible supports. Forexample, the supports can direct the light emitted by the light sourceto be directional or non-directional. In some instances, the lightsource can comprise primary and/or secondary optical elements. In someinstances, the light source can comprise tertiary optical elements. Insome instances, the light source can comprise other optical elements atother levels or layers (e.g., lens, reflector, diffusor, beam splitter,etc.). The light source can be configured to convert electrical energyto optical energy. For example, the light source can be powered by anelectrical power source, which may be external or internal to the photonbattery assembly 100. The light source can be configured to emit opticalenergy (e.g., as photons), such as in the form of electromagnetic waves.In some instances, the light source can be configured to emit opticalenergy at a wavelength or a range of wavelengths that is capable ofbeing absorbed by the phosphorescent material 102. For example, thelight source can emit light at wavelengths in the ultraviolet range(e.g., 10 nanometers (nm) to 400 nm). In some instances, the lightsource can emit light at other wavelengths or ranges of wavelengths inthe electromagnetic spectrum (e.g., infrared, visible, ultraviolet,x-rays, etc.).

In some instances, the light source 101 can be a natural light source(e.g., sun light), in which case the phosphorescent material 102 in thephoton battery assembly 100 may be exposed to the natural light sourceto absorb such natural light.

The phosphorescent material 102 can absorb optical energy at a firstwavelength (or first wavelength range) and emit optical energy at asecond wavelength (or second wavelength range) after a substantial timedelay. The second wavelength can be a different wavelength than thefirst wavelength. The optical energy at the first wavelength that isabsorbed by the phosphorescent material can be at a higher energy levelthan the optical energy at the second wavelength that is emitted by thephosphorescent material. The second wavelength can be greater than thefirst wavelength. In an example, the phosphorescent material can absorbenergy at ultraviolet range wavelengths (e.g., 10 nm to 400 nm) and emitenergy at visible range wavelengths (e.g., 400 nm to 700 nm). Forexample, the phosphorescent material can absorb blue photons and, aftera time delay, emit green photons. The phosphorescent material can absorboptical energy (e.g., photons) at other wavelengths (or ranges ofwavelengths) and emit optical energy at other wavelengths (or ranges ofwavelengths), such as in the electromagnetic spectrum (e.g., infrared,visible, ultraviolet, x-rays, etc.) wherein the energy emitted is at alower energy level than the energy absorbed. A rate of emission ofoptical energy by the phosphorescent material can be slower than a rateof absorption of optical energy by the phosphorescent material. Anadvantage of this difference in rate is the ability of thephosphorescent material to release energy at a slower rate thanabsorbing such energy, thus storing the energy during such time delay.

The phosphorescent material 102 can be crystalline, solid, liquid,ceramic, in powder form, granular or other particle form, liquid form,or in any other shape, state, or form. The phosphorescent material canbe long-lasting phosphors. In an example, the phosphorescent materialcan comprise strontium aluminate doped with europium (e.g., SrAl₂O₄:Eu).Some other examples of phosphorescent material can include, but are notlimited to, zinc gallogermanates (e.g., Zn₃Ga₂Ge₂O₁₀:0.5% Cr³⁺), zincsulfide doped with copper and/or cobalt (e.g., ZnS:Cu, Co), strontiumaluminate doped with other dopants, such as europium, dysprosium, and/orboron (e.g., SrAl₂O₄:Eu²⁺, Dy³⁺, B³⁺), calcium aluminate doped witheuropium, dysprosium, and/or neodymium (e.g., CaAl₂O₄:Eu²⁺, Dy³⁺, Nd³⁺),yttrium oxide sulfide doped with europium, magnesium, and/or titanium,(e.g., Y₂O₂S:Eu³⁺, Mg²⁺, Ti⁴⁺), and zinc gallogermanates (e.g.,Zn₃Ga₂Ge₃O₃:0.5% Cr³⁺). In some instances, the phosphorescent materialmay be provided in granular or other particle form. Such grain orparticle may have a maximum diameter of between about 1 and about 5micrometer. In some instances, the grain or particle may have a maximumdiameter of at least about 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8,1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2,3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6,4.7, 4.8, 4.9, 5.0 micrometers or more. Alternatively or in addition,the grain or particle may have a maximum diameter of at most about 5.0,4.9, 4.8, 4.7, 4.6, 4.5, 4.4, 4.3, 4.2, 4.1, 4.0, 3.9, 3.8, 3.7, 3.6,3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2,2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0 micrometersor less.

In some instances, the afterglow (e.g., emitted optical energy) emittedby the phosphorescent material can last at least about 1 hour (hr), 2hr, 3 hr, 4 hr, 5 hr, 6 hr, 7 hr, 8 hr, 9 hr, 10 hr, 11 hr, 12 hr, 1day, 2 days, 3 days, 4 days, 1 week, 2 weeks, 3 weeks, or longer. Insome instances, the phosphorescent material can store and/or dischargeenergy for at least about 1 hr, 2 hr, 3 hr, 4 hr, 5 hr, 6 hr, 7 hr, 8hr, 9 hr, 10 hr, 11 hr, 12 hr, 1 day, 2 days, 3 days, 4 days, 1 week, 2weeks, 3 weeks, or longer. Alternatively, the afterglow emitted by thephosphorescent material (or energy stored by the phosphorescentmaterial) can last for shorter durations.

In some instances, the phosphorescent material 102 may absorb opticalenergy at the first wavelength from any direction. In some instances,the phosphorescent material may emit optical energy at the secondwavelength in any direction (e.g., from a surface of the phosphorescentmaterial).

The assembly 100 can comprise one or a plurality of photovoltaic cells(e.g., photovoltaic cell 103) that are electrically connected in seriesand/or in parallel. The photovoltaic cell 103 can be a panel, cell,module, and/or other unit. For example, a panel can comprise one or morecells all oriented in a plane of the panel and electrically connected invarious configurations. For example, a module can comprise one or morecells electrically connected in various configurations. The photovoltaiccell 103, or solar cell, can be configured to absorb optical energy andgenerate electrical power from the absorbed optical energy. In someinstances, the photovoltaic cell can be configured to absorb opticalenergy at a wavelength or a range of wavelengths that is capable ofbeing emitted by the phosphorescent material 102. The photovoltaic cellcan have a single band gap that is tailored to the wavelength (or rangeof wavelengths) of the optical energy that is emitted by thephosphorescent material. Beneficially, this may increase the efficiencyof the energy storage system of the photon battery assembly 100. Forexample, for strontium aluminate doped with europium as thephosphorescent material, the photovoltaic cell can have a band gap thatis tailored to the green light wavelength (e.g., 500˜520 nm). Similarly,the light source 101 can be tailored to emit ultraviolet rangewavelengths (e.g., 20 nm to 400 nm). Alternatively, the photovoltaiccell can be configured to absorb optical energy at other wavelengths (orranges of wavelengths) in the electromagnetic spectrum (e.g., infrared,visible, ultraviolet, x-rays, etc.).

In some embodiments, organic light emitting diodes (OLEDs) can replacethe phosphorescent material 102 in the photon battery assembly 100. Insome embodiments, OLEDs can replace both the light source 101 and thephosphorescent material. OLEDs can be capable ofelectro-phosphorescence, where quasi particles in the lattice of thediodes store potential energy from an electric power source and releasesuch energy over time in the form of optical energy at visiblewavelengths (e.g., 400 nm to 700 nm). For example, OLEDs can be poweredby an electrical power source, which may be external or internal to thephoton battery assembly 100. A light-emitting surface of the OLEDs caninterface with a light-absorbing surface of the photovoltaic cell 103 tocomplete the photon battery assembly. For example, with OLEDs, thephotovoltaic cell can have a band gap that is tailored to the visiblewavelength range (e.g., 400˜700 nm).

The photovoltaic cell 103 may have any thickness. For example, thephotovoltaic cell may have a thickness of about 20 micrometers. In someinstances, the photovoltaic cell may have a thickness of at least about10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,28, 29, 30, 40, 50, 60, 70, 80, 90, 100 micrometers or more.Alternatively, the photovoltaic cell may have a thickness of at mostabout 100, 90, 80, 70, 60, 50, 40, 30, 29, 28, 27, 26, 25, 24, 23, 22,21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10 micrometers or less.

FIG. 2 shows a photon battery in communication with an electrical load.The photon battery 201 can power an electrical load 202. The photonbattery and the electrical load can be in electric communication, suchas via an electric circuit. While FIG. 2 shows a circuit, the circuitconfiguration is not limited to the one shown in FIG. 2. The electricalload can be an electrical power consuming device. The electrical loadcan be an electronic device, such as a personal computer (e.g., portablePC), slate or tablet PC (e.g., Apple® iPad, Samsung® Galaxy Tab),telephone, Smart phone (e.g., Apple® iPhone, Android-enabled device,Blackberry®), or personal digital assistant. The electronic device canbe mobile or non-mobile. The electrical load can be a vehicle, such asan automobile, electric car, train, boat, or airplane. The electricalload can be a power grid. In some cases, the electrical load can beanother battery or other energy storage system which is charged by thephoton battery. In some instances, the photon battery can be integratedin the electrical load. In some instances, the photon battery can bepermanently or detachably coupled to the electrical load. For example,the photon battery can be removable from the electrical load.

In some cases, a photon battery 201 can power a plurality of electricalloads in series or in parallel. In some cases, a photon battery canpower a plurality of electrical loads simultaneously. For example, thephoton battery can power 2, 3, 4, 5, 6, 7, 8, 9, 10 or more electricalloads simultaneously. In some cases, a plurality of photon batteries,electrically connected in series or in parallel, can power an electricalload. In some cases, a combination of one or more photon batteries andone or more other types of energy storage systems (e.g., lithium ionbattery, fuel cell, etc.) can power one or more electrical loads.

FIG. 3 shows an exemplary photon battery assembly in application. Anyand all circuits illustrated in FIG. 3 are not limited to such circuitryconfigurations. A photon battery assembly 300 can be charged by a powersource 304 and discharge power to an electrical load 306. The photonbattery assembly can comprise a light source 301, such as a LED or a setof LEDs. The light source can be in electrical communication with thepower source 304 through a port 305 of the light source. For example,the power source and the port 305 can be electrically connected via acircuit. The power source 304 may be external or internal to the photonbattery assembly 300. The power source can be a power supplying device,such as another energy storage system (e.g., another photon battery,lithium ion battery, supercapacitor, fuel cell, etc.). The power sourcecan be an electrical grid.

The light source 301 can receive electrical energy and emit opticalenergy at a first wavelength, such as via a light-emitting surface ofthe light source. The light-emitting surface can be adjacent to aphosphorescent material 302. The light source can be in opticalcommunication with the phosphorescent material. The phosphorescentmaterial can be configured to absorb optical energy at the firstwavelength and, after a time delay, emit optical energy at a secondwavelength. In some cases, the rate of emission of the optical energy atthe second wavelength can be slower than the rate of absorption of theoptical energy at the first wavelength. An advantage of this differencein rate is the ability of the phosphorescent material to release energyat a slower rate than absorbing such energy, thus storing the energyduring such time delay. In some instances, the phosphorescent materialcan store and/or discharge energy for at least about 1 hr, 2 hr, 3 hr, 4hr, 5 hr, 6 hr, 7 hr, 8 hr, 9 hr, 10 hr, 11 hr, 12 hr, 1 day, 2 days, 3days, 4 days, 1 week, 2 weeks, 3 weeks, or longer.

The photon battery assembly can comprise a photovoltaic cell 303. Thephotovoltaic cell can be configured to absorb optical energy at thesecond wavelength, such as via a light-absorbing surface of thephotovoltaic cell. The photovoltaic cell can be in optical communicationwith the phosphorescent material 302. The light-absorbing surface of thephotovoltaic cell can be adjacent to the phosphorescent material. Thephotovoltaic cell can generate electrical power from the optical energyabsorbed. The electrical power generated by the photovoltaic cell can beused to power an electrical load 306. The photovoltaic cell can be inelectrical communication with the electrical load through a port 307 ofthe photovoltaic cell. For example, the electrical load and the port 307can be electrically connected via a circuit.

The energy stored by the photon battery assembly 300 can be chargedand/or recharged multiple times. The power generated by the photonbattery assembly can be consumed multiple times. The photon batteryassembly can be charged and/or recharged by supplying electrical energy(or power) to the light source 301, such as through the port 305. Thephoton battery assembly 300 can discharge power by directing electricalpower generated by the photovoltaic cell to the electrical load 306,such as through the port 307. For example, the photon battery assembly300 can last (e.g., function for) at least 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 100, 500, 1000, 10⁴, 10⁵, 10⁶, or more recharge (or consumption)cycles.

The photon battery assembly 300 may provide superior charging rates tothose of conventional chemical batteries, for example, on the order of2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 timesfaster or more. For example, the photon battery assembly can charge at aspeed of at least about 800 watts per cubic centimeters (W/cc), 850W/cc, 900 W/cc, 1000 W/cc, 1050 W/cc, 1100 W/cc, 1150 W/cc, 1200 W/cc,1250 W/cc, 1300 W/cc, 1350 W/cc, 1400 W/cc, 1450 W/cc, 1500 W/cc orgreater. Alternatively, the photon battery assembly can charge at aspeed of less than about 800 W/cc. The photon battery assembly mayprovide superior lifetimes to those of conventional chemical batteries,for example, on the order of 2, 3, 4, 5, 6, 7, 8, 9, 10 times morerecharge cycles or more.

The photon battery assembly 300 may be stable and function effectivelyin relatively cold operating temperature conditions. For example, thephoton battery assembly may function stably in operating temperatures aslow as about −55° Celsius (° C.) and as high as about 65° C. The photonbattery assembly may function stably in operating temperatures lowerthan about −55° C. and higher than about 65° C. In some instances, thephoton battery assembly may function stably under any operatingtemperatures for which the light source (e.g., LEDs) functions stably.The photon battery assembly may not generate excess operating heat.

FIG. 4A illustrates a photon battery assembly with a waveguide. A photonbattery assembly 400 can comprise a light source 401, a phosphorescentmaterial 402, a photovoltaic cell (not shown), and a waveguide 404. Thewaveguide may be adjacent to the light source and the phosphorescentmaterial. For example, the waveguide may be sandwiched by the lightsource and the phosphorescent material. In other examples, as shown inFIG. 4A, some surfaces of the waveguide may be adjacent to thephosphorescent material and some surfaces of the waveguide may beadjacent to the light source. In some instances, additionally, thewaveguide may be adjacent to the photovoltaic cell. The configuration ofthe photon battery assembly with the waveguide is not limited to FIG.4A.

Regardless of contact between the phosphorescent material 402 andwaveguide 404, the phosphorescent material and the waveguide may be inoptical communication. Regardless of contact between the light source401 and waveguide, the light source and the waveguide may be in opticalcommunication. In some instances, regardless of contact between thephotovoltaic cell and waveguide, the photovoltaic cell and the waveguidemay be in optical communication.

The waveguide 404 may or may not be contacting the light source 401. Ifthe waveguide and the light source are in contact, the waveguide caninterface a light-emitting surface of the light source. The waveguideand the light source can be coupled or fastened together at theinterface, such as via a fastening mechanism. In some instances, asupport carrying the light source and/or a support carrying thewaveguide may be coupled or fastened together at the interface. Examplesof fastening mechanisms may include, but are not limited to,form-fitting pairs, hooks and loops, latches, staples, clips, clamps,prongs, rings, brads, rubber bands, rivets, grommets, pins, ties, snaps,velcro, adhesives, tapes, a combination thereof, or any other types offastening mechanisms. In some instances, the waveguide may have adhesiveand/or cohesive properties and adhere to the light source without anindependent fastening mechanism. The waveguide and the light source canbe permanently or detachably fastened together. For example, thewaveguide and the light source can be disassembled from and reassembledinto the photon battery assembly 400 without damage (or with minimaldamage) to waveguide and/or the light source. Alternatively, while incontact, the waveguide and the light source may not be fastenedtogether.

If the waveguide 404 and the light source 401 are not in contact, thewaveguide can otherwise be in optical communication with alight-emitting surface of the light source. For example, the waveguidecan be positioned in an optical path of light emitted by thelight-emitting surface of the light source. In some instances, there canbe an air gap between the waveguide and the light source. In someinstances, there can be another intermediary layer, such as a solidmaterial (e.g., glass, plastic, etc.) and/or another waveguide, betweenthe waveguide and the light source. The intermediary layer can be airand/or other fluid. The intermediary layer can be a light guide oranother layer of optical elements (e.g., lens, reflector, diffusor, beamsplitter, etc.). In some instances, there can be a plurality ofintermediary layers between the waveguide and the light source. In someinstances, the waveguide may be in optical communication with one ormore surfaces of the waveguide. For example, the light source maycomprise an array and/or row of LEDs that are in optical communicationwith one or more surfaces of the waveguide. The waveguide may receivelight from the light source from any surface. In some instances, asurface of the waveguide in optical communication with a surface of alight source may be parallel, perpendicular, or at any angle whether indirect contact or not in contact. Either or both surfaces may be flat.Either or both surfaces may be angled and/or have a curvature (e.g.,convex, concave). Either or both surfaces may have any surface profile.

The waveguide 404 may or may not be contacting the phosphorescentmaterial 402. If the waveguide and the phosphorescent material are incontact, the waveguide can interface a light-absorbing surface of thephosphorescent material. The waveguide and the phosphorescent materialcan be coupled or fastened together at the interface, such as via afastening mechanism. In some instances, a support carrying thephosphorescent material and/or a support carrying the waveguide may becoupled or fastened together at the interface. Examples of fasteningmechanisms may include, but are not limited to, form-fitting pairs,hooks and loops, latches, staples, clips, clamps, prongs, rings, brads,rubber bands, rivets, grommets, pins, ties, snaps, velcro, adhesives,tapes, a combination thereof, or any other types of fasteningmechanisms. In some instances, the waveguide may have adhesive and/orcohesive properties and adhere to the phosphorescent material without anindependent fastening mechanism. In some instances, the phosphorescentmaterial may have adhesive and/or cohesive properties and adhere to thewaveguide without an independent fastening mechanism. For example, thephosphorescent material may be painted or coated on a light-emittingsurface of the waveguide. The waveguide and the phosphorescent materialcan be permanently or detachably fastened together. For example, thewaveguide and the phosphorescent material can be disassembled from andreassembled into the photon battery assembly 400 without damage (or withminimal damage) to waveguide and/or the phosphorescent material.Alternatively, while in contact, the waveguide and the phosphorescentmaterial may not be fastened together.

If the waveguide 404 and the phosphorescent material 402 are not incontact, the waveguide can otherwise be in optical communication with alight-absorbing surface of the phosphorescent material. For example, thephosphorescent material can be positioned in an optical path of lightemitted by the light-emitting surface of the waveguide. In someinstances, there can be an air gap between the waveguide and thephosphorescent material. In some instances, there can be anotherintermediary layer, such as another waveguide, between the waveguide andthe phosphorescent material. The intermediary layer can be air or otherfluid. The intermediary layer can be a light guide or another layer ofoptical elements (e.g., lens, reflector, diffusor, beam splitter, etc.).In some instances, there can be a plurality of intermediary layersbetween the waveguide and the phosphorescent material. In someinstances, the waveguide may be in optical communication with one ormore surfaces of the phosphorescent material. The phosphorescentmaterial may receive light from the waveguide from any surface. In someinstances, a surface of the waveguide in optical communication with asurface of a phosphorescent material may be parallel, perpendicular, orat any angle, whether in direct contact or not in contact. Either orboth surfaces may be flat. Either or both surfaces may be angled and/orhave a curvature (e.g., convex, concave). Either or both surfaces mayhave any surface profile.

The waveguide 404 may be configured to direct waves at a firstwavelength emitted from the light source 401 to the phosphorescentmaterial 402. Beneficially, the waveguide may deliver optical energyfrom the light source to the phosphorescent material with greatefficiency and minimal loss of optical energy (or other forms ofenergy). The waveguide may provide optical communication between thelight source and distributed volumes of the phosphorescent materialwhere otherwise some volumes of phosphorescent material would not be inoptical communication with the light source, allowing for flexiblearrangements of the light source relative to the phosphorescentmaterial. For example, without waveguides, the optical energy at thefirst wavelength emitted from the light source may be absorbed mostefficiently by the immediately adjacent volume of phosphorescentmaterial (relative to the light source or otherwise in immediate opticalcommunication with the light source), such as at the phosphorescentmaterial-light source interface. However, once such immediately adjacentphosphorescent material absorbs the optical energy at the firstwavelength, it may no longer have capacity to receive further opticalenergy and/or prevent other volumes of phosphorescent material (furtherdownstream in the optical path) from absorbing such optical energy.While large surface area interface between the phosphorescent materialand the light source may facilitate efficient optical energy deliveryfrom the light source to the phosphorescent material, this may beimpractical when constructing compact energy storage systems. Byimplementing waveguides to facilitate optical communication between thelight source and the phosphorescent material, different volumes of thephosphorescent material may evenly absorb the optical energy from thelight source even if such phosphorescent material and the light sourceare not immediately adjacent.

The waveguide 404 may have a maximum dimension (e.g., width, length,height, radius, diameter, etc.) of at least about 10 micrometers, 20micrometers, 30 micrometers, 40 micrometers, 50 micrometers, 60micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100micrometers, 200 micrometers, 300 micrometers, 400 micrometers, 500micrometers, 600 micrometers, 700 micrometers, 800 micrometers, 900micrometers, 1 millimeter (mm), 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8mm, 9 mm, 1 centimeter (cm), 2 cm, 3 cm, 4 cm, 5 cm, 10 cm, 15 cm, 20cm, 30 cm, 40 cm, 50 cm or more. Alternatively or in addition, thewaveguide may have a maximum dimension of at most about 50 cm, 40 cm, 30cm, 20 cm, 15 cm, 10 cm, 5 cm, 4 cm, 3 cm, 2 cm, 1 cm, 9 mm, 8 mm, 7 mm,6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 900 micrometers, 800 micrometers,700 micrometers, 600 micrometers, 500 micrometers, 400 micrometers, 300micrometers, 200 micrometers, 100 micrometers, 90 micrometers, 80micrometers, 70 micrometers, 60 micrometers, 50 micrometers, 40micrometers, 30 micrometers, 20 micrometers, 10 micrometers, or less.The waveguide may be square, rectangular (e.g., having an aspect ratiofor length to width of about 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6,1:1.7, 1:1.8, 1:1.9, 1:2, 1:3, 1:4, 1:5, 1:10, etc.), or any othershape. The waveguide may comprise material such as plastic or glass. Thewaveguide may comprise material used in an injection mold.

For example, in FIG. 4A, the optical energy emitted from the lightsource 401 is directed through the layer of waveguide 404 to reachvarious locations of the phosphorescent material 402. As describedelsewhere herein, after a time delay, the phosphorescent material 402may emit optical energy at the second wavelength for absorption by aphotovoltaic cell (not shown). The waveguide may comprise one or morereflective surfaces 405 to direct waves from the light source to thephosphorescent material. The one or more reflective surfaces may haveincreasingly large reflective surfaces in the optical path within thewaveguide to allow some waves to be reflected at a first reflectivesurface for excitation of a first volume of phosphorescent material, andsome waves to travel further before being reflected at a secondreflective surface for excitation of a second volume of phosphorescentmaterial that is further from the light source than the first volume,and some waves to travel further before being reflected at a thirdreflective surface for excitation of a third volume of phosphorescentmaterial that is further than the second volume, and so on. There may beany number of reflective surfaces in the waveguide. For example, theremay be at least about 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70,80, 90, 100, 200, 300, 400, 500, or more reflective surfaces.Alternatively or in addition, a single reflective surface may graduallyincrease surface area, such as in a conical shape, in the optical pathwithin the waveguide to achieve a similar outcome.

In some instances, the waveguide may be adjacent to the phosphorescentmaterial from a first surface, and adjacent to the light source from asecond surface, wherein the first surface and the second surface aresubstantially orthogonal. The one or more reflective surfaces may beconfigured to direct waves in a substantially orthogonal direction suchas to receive from the light source from the second surface and totransmit through the first surface. Alternatively or in addition, thefirst surface and the second surface may be at any other angle and theone or more reflective surfaces may be configured to direct waves in theother angle, such as to receive from the light source from the secondsurface and to transmit through the first surface. As illustrated inFIG. 4A, the waveguide may be adjacent to a plurality of layers ofphosphorescent material (e.g., interfacing different surfaces of thewaveguide). The one or more reflective surfaces may be configured todirect waves received from the light source to the plurality of layersof phosphorescent material by reflecting the waves (e.g., light) to theplurality of layers.

In some instances, alternative to or in addition to the light source401, the photon battery assembly 400 may be charged (or thephosphorescent material excited) wirelessly. In some embodiments, aphoton battery assembly can comprise the phosphorescent material 402, aphotovoltaic cell (not shown), and the waveguide 404, without having thelight source 401 integrated in the assembly. For example, the lightsource 401 (illustrated in FIG. 4A) can be remote and detached from theother components. The light source may be driven by a power source thatis separate and/or detached from the photon battery assembly that itcharges. Such remote light source can be configured to provide opticalenergy to the assembly to achieve wireless charging of the assembly.Regardless of where the light source 401 is disposed with respect to theassembly and/or the waveguide, the light source may be in opticalcommunication with the waveguide and/or the phosphorescent material toprovide optical energy for excitation of the phosphorescent material.The remote light source can be configured to provide optical energy at ahigher energy level than the optical energy emitted by thephosphorescent material. For example, where the phosphorescent materialis strontium aluminate, the remote light source may provide opticalenergy at wavelengths that is shorter than the emission wavelength ofabout 520 nanometers. For example, the remote light source may providewaves at wavelengths between about 300 nanometers to about 470nanometers. The remote light source may provide such optical energy viaLED, lasers, or other optical beams, as described elsewhere herein. Insome instances, a photon battery assembly configuration may maximize (orotherwise) increase the exposed surface area of one or more waveguidesand/or the phosphorescent material to facilitate such wireless charging.Beneficially, the compactness and the transportability of the photonbattery assemblies described herein may be greatly increased by allowingfor wireless charging. Further, such wireless charging may allow forfast charging, optical charging, and on-demand charging, as well asbenefit from the general widespread availability of charging sources(e.g., availability of light sources). Any of the photon batteryassemblies may be configured for wireless charging, either in additionto wired (e.g., integrated) light source charging, or alternative tointegrated light source charging.

In some instances, the waveguide may be coated at one or more surfaces.Otherwise, the waveguide may be adjacent to and/or in contact withanother layer at one or more surfaces. For example, the waveguide may becoated at one or more surfaces that interfaces the phosphorescentmaterial 402. An example coating configuration is shown in FIG. 4B. Aphoton battery assembly can comprise a light source (not shown), aphosphorescent material 452, a photovoltaic cell 453, and a waveguide451, which has a coating 454 on one or more of its surfaces thatinterfaces the phosphorescent material. The waveguide may be adjacent tothe light source and the phosphorescent material, as described elsewhereherein.

The coating 454 may be disposed between the waveguide 451 and thephosphorescent material 452. In some instances, all surfaces of thewaveguide interfacing (or in optical communication with) thephosphorescent material may be covered by the coating. In otherinstances, a portion of the surfaces interfacing (or in opticalcommunication with) the phosphorescent material may be covered by thecoating and a portion of the surfaces interfacing (or in opticalcommunication with) the phosphorescent material may not be covered bythe coating. For example, such surfaces may be uncovered by anything andin direct optical communication with the phosphorescent material, or becovered by another coating or another layer (e.g., glass, anotherwaveguide, etc.) and be in optical communication with the phosphorescentmaterial through the other coating or other layer. In some instances,the other layer can be a light guide or another layer of opticalelements (e.g., lens, reflector, diffusor, beam splitter, etc.). In someinstances, there may be a plurality of layers between the waveguide 451and the phosphorescent material 452, including the coating 454. Forexample, the plurality of layers may include an air gap or other fluidgap, a solid layer (e.g., glass, plastic.), other optical elements(e.g., lens, reflector, diffusor, beam splitter, etc.), and/or any otherlayer, in any combination, and arranged in any order or sequence.Regardless of coating or waveguide configuration, the phosphorescentmaterial 452 and the waveguide 451 may be in optical communication.

The waveguide 404 may or may not be contacting the coating 454. Thewaveguide and the coating can be coupled or fastened together at theinterface, such as via a fastening mechanism. In some instances, asupport carrying the coating and/or a support carrying the waveguide maybe coupled or fastened together at the interface. Examples of fasteningmechanisms may include, but are not limited to, form-fitting pairs,hooks and loops, latches, staples, clips, clamps, prongs, rings, brads,rubber bands, rivets, grommets, pins, ties, snaps, velcro, adhesives,tapes, a combination thereof, or any other types of fasteningmechanisms. In some instances, the coating may have adhesive and/orcohesive properties and adhere to the waveguide without an independentfastening mechanism. In some instances, the waveguide may have adhesiveand/or cohesive properties and adhere to the coating without anindependent fastening mechanism. For example, the coating may be paintedor coated on a surface of the waveguide. The waveguide and the coatingcan be permanently or detachably fastened together. For example, thewaveguide and the coating can be disassembled from and reassembled intothe photon battery assembly without damage (or with minimal damage) towaveguide and/or the coating. Alternatively, while in contact, thewaveguide and the coating may not be fastened together.

The coating 454 may be a dichroic coating or comprise other opticalfilter(s). For example, the coating may be configured to allow waves atcertain first wavelength(s) (e.g., longer wavelength) in to excite thephosphorescent material 452, but reflect the waves at certain secondwavelength(s) (e.g., shorter wavelength). For example, waves with longerwavelength(s) may be allowed to reach the phosphorescent materialthrough the coating, and waves with shorter wavelengths(s) emitted bythe phosphorescent material may be reflected by the coating and keptwithin the phosphorescent material layer to (i) increase the likelihoodthat such waves with shorter wavelengths are incident upon thephotovoltaic cell 453, and (ii) prevent such waves from entering thewaveguide 451 and generating undesired heat.

The coating 454 may have any thickness. For example, the coating may bebetween 0.5 micrometers and 5 micrometers. In some instances, thecoating may be at least about 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2,1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6,2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0,4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0 micrometers or more inthickness. Alternatively or in addition, the coating may be at mostabout 5.0, 4.9, 4.8, 4.7, 4.6, 4.5, 4.4, 4.3, 4.2, 4.1, 4.0, 3.9, 3.8,3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4,2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0,0.9, 0.8, 0.7, 0.6, 0.5 micrometers or less in thickness.

Alternatively or in addition to the coating 454, the waveguide 451 maycomprise a surface feature 455 (or multiple features) to facilitate thedirection of waves towards a certain direction, and/or increase theuniformity of the direction in which waves are directed. For example,one or more surfaces of the waveguide may comprise physical structuresor features, such as grooves, troughs, indentations, hills, pillars,walls, and/or other structures or features. In an example, a bottomsurface of the waveguide may comprise one or more grooves formed inwardsthe waveguide such that waves from the light source are uniformlyreflected in a direction towards the phosphorescent material to excitethe phosphorescent material. Such grooves (and/or other physicalstructures or features) may be patterned into the waveguide. Thepatterns may be regular or irregular. For example, the grooves may bespaced at regular intervals or irregularly spaced. In some instances,such grooves (and/or other physical structures or features) may bediscrete features. The physical structure or feature may be formed byany mechanism, such as mechanical machining. In some instances, diamondturning can be used to etch or cut the physical structures or features(e.g., grooves) into the waveguide. In some instances, one or morephysical features may be integral to the waveguide. In some instances,one or more physical features may be external to, and/or otherwisecoupled/attached to the waveguide by any fastening mechanism describedelsewhere herein. Alternatively or in addition to the coating 454 and/orthe surface feature 455, the waveguide 451 may further comprise surfacemarking to facilitate the direction of waves towards a certaindirection. For example, one or more surfaces of the waveguide maycomprise painted markings having certain optical properties thatfacilitating the scattering of waves in a certain direction. Forexample, such painted markings may be white painted dots that facilitatescatter of light towards the phosphorescent material to excite thephosphorescent material. The waveguide may comprise any number of suchpainted dots (or other surface markings). The waveguide may comprise anytype of painted markings, including other colored dots. The markings mayform a pattern. The patterns may be regular or irregular. For example,the dots may be spaced at regular intervals or irregularly spaced. Insome instances, such dots may be discrete markings.

Any of the photon battery assemblies described herein may comprise awaveguide in optical communication with an optical filter, such as thedichroic coating described with respect to FIG. 4B, or comprise awaveguide comprising the physical features and/or markings describedwith respect to FIG. 4B. For example, the photon battery assembly 100 ofFIG. 1 may comprise a waveguide (not shown) in optical communicationwith a coating disposed between the waveguide and the phosphorescentmaterial 102. For example, the photon battery assembly 400 of FIG. 4Amay comprise a coating disposed between the waveguide 404 and thephosphorescent material 402.

FIG. 5 illustrates another photon battery assembly with a waveguide. Aphoton battery assembly 500 can comprise a light source (not shown), aphosphorescent material 502, a photovoltaic cell 503, and a waveguide506. The waveguide may be adjacent to the photovoltaic cell and thephosphorescent material. For example, the waveguide may be sandwiched bythe photovoltaic cell and the phosphorescent material. In otherexamples, as shown in FIG. 5, some surfaces of the waveguide may beadjacent to the phosphorescent material and some surfaces of thewaveguide may be adjacent to the photovoltaic cell. In some instances,additionally, the waveguide may be adjacent to the light source. Theconfiguration of the photon battery assembly with the waveguide is notlimited to FIG. 5.

Regardless of contact between the phosphorescent material 502 andwaveguide 506, the phosphorescent material and the waveguide may be inoptical communication. Regardless of contact between the photovoltaiccell 503 and waveguide, the photovoltaic cell and the waveguide may bein optical communication. In some instances, regardless of contactbetween the light source and waveguide, the light source and thewaveguide may be in optical communication.

The waveguide 506 may or may not be contacting the photovoltaic cell503. If the waveguide and the photovoltaic cell are in contact, thewaveguide can interface a light-absorbing surface of the photovoltaiccell. The waveguide and the photovoltaic cell can be coupled or fastenedtogether at the interface, such as via a fastening mechanism. In someinstances, a support carrying the photovoltaic cell and/or a supportcarrying the waveguide may be coupled or fastened together at theinterface. Examples of fastening mechanisms may include, but are notlimited to, form-fitting pairs, hooks and loops, latches, staples,clips, clamps, prongs, rings, brads, rubber bands, rivets, grommets,pins, ties, snaps, velcro, adhesives, tapes, a combination thereof, orany other types of fastening mechanisms. In some instances, thewaveguide may have adhesive and/or cohesive properties and adhere to thephotovoltaic cell without an independent fastening mechanism. Thewaveguide and the photovoltaic cell can be permanently or detachablyfastened together. For example, the waveguide and the photovoltaic cellcan be disassembled from and reassembled into the photon batteryassembly 500 without damage (or with minimal damage) to waveguide and/orthe photovoltaic cell. Alternatively, while in contact, the waveguideand the photovoltaic cell may not be fastened together.

If the waveguide 506 and the photovoltaic cell 503 are not in contact,the waveguide can otherwise be in optical communication with alight-emitting surface of the photovoltaic cell. For example, thephotovoltaic cell can be positioned in an optical path of light emittedby a light-emitting surface of the waveguide. In some instances, therecan be an air gap between the waveguide and the photovoltaic cell. Insome instances, there can be another intermediary layer, such as anotherwaveguide, between the waveguide and the photovoltaic cell. Theintermediary layer can be air or other fluid. The intermediary layer canbe a light guide or another layer of optical elements (e.g., lens,reflector, diffusor, beam splitter, etc.). In some instances, there canbe a plurality of intermediary layers between the waveguide and thephotovoltaic cell.

The waveguide 506 may or may not be contacting the phosphorescentmaterial 502. If the waveguide and the phosphorescent material are incontact, the waveguide can interface a light-emitting surface of thephosphorescent material. The waveguide and the phosphorescent materialcan be coupled or fastened together at the interface, such as via afastening mechanism. In some instances, a support carrying thephosphorescent material and/or a support carrying the waveguide may becoupled or fastened together at the interface. Examples of fasteningmechanisms may include, but are not limited to, form-fitting pairs,hooks and loops, latches, staples, clips, clamps, prongs, rings, brads,rubber bands, rivets, grommets, pins, ties, snaps, velcro, adhesives,tapes, a combination thereof, or any other types of fasteningmechanisms. In some instances, the waveguide may have adhesive and/orcohesive properties and adhere to the phosphorescent material without anindependent fastening mechanism. In some instances, the phosphorescentmaterial may have adhesive and/or cohesive properties and adhere to thewaveguide without an independent fastening mechanism. For example, thephosphorescent material may be painted or coated on the waveguide. Thewaveguide and the phosphorescent material can be permanently ordetachably fastened together. For example, the waveguide and thephosphorescent material can be disassembled from and reassembled intothe photon battery assembly 500 without damage (or with minimal damage)to waveguide and/or the phosphorescent material. Alternatively, while incontact, the waveguide and the phosphorescent material may not befastened together.

If the waveguide 506 and the phosphorescent material 502 are not incontact, the waveguide can otherwise be in optical communication with alight-emitting surface of the phosphorescent material. In someinstances, there can be another intermediary layer, such as anotherwaveguide, between the waveguide and the phosphorescent material. Theintermediary layer can be air or other fluid. The intermediary layer canbe a light guide or another layer of optical elements (e.g., lens,reflector, diffusor, beam splitter, etc.). In some instances, there canbe a plurality of intermediary layers between the waveguide and thephosphorescent material.

The waveguide 506 may be configured to direct waves at a secondwavelength emitted from the phosphorescent material 502 to thephotovoltaic cell 503. Beneficially, the waveguide may deliver opticalenergy from the phosphorescent material to the photovoltaic cell withgreat efficiency and minimal loss of optical energy (or other forms ofenergy). The phosphorescent material may emit optical energy at thesecond wavelength without directional specificity, such as in isotropicemission. The waveguide may provide optical communication between thephotovoltaic cell and distributed volumes of the phosphorescent materialwhere otherwise some volumes of phosphorescent material would not be inoptical communication with the photovoltaic cell, allowing for flexiblearrangements of the photovoltaic cell relative to the phosphorescentmaterial. For example, without waveguides, the optical energy at thesecond wavelength emitted from the phosphorescent material may beabsorbed most efficiently by the immediately adjacent light absorbingsurface of the photovoltaic cell, if it reaches the photovoltaic cell atall. The optical energy that is emitted away from the light absorbingsurface of the photovoltaic cell may be lost in the process. While largesurface area interface between the phosphorescent material and thephotovoltaic cell may facilitate efficient optical energy delivery fromthe phosphorescent material to the photovoltaic cell, this may beimpractical and expensive when constructing compact energy storagesystems. By implementing waveguides to facilitate optical communicationbetween the photovoltaic cell and the phosphorescent material, thephotovoltaic cell may efficiently absorb the optical energy from thephosphorescent material even if they are not immediately adjacent.

The waveguide 506 may have a maximum dimension (e.g., width, length,height, radius, diameter, etc.) of at least about 1 millimeter (mm), 2mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 1 centimeter (cm), 2 cm, 3cm, 4 cm, 5 cm, 10 cm, 15 cm, 20 cm, 30 cm, 40 cm, 50 cm or more.Alternatively or in addition, the waveguide may have a maximum dimensionof at most about 50 cm, 40 cm, 30 cm, 20 cm, 15 cm, 10 cm, 5 cm, 4 cm, 3cm, 2 cm, 1 cm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm orless. The waveguide may be square, rectangular (e.g., having an aspectratio for length to width of about 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5,1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:3, 1:4, 1:5, 1:10, etc.), or anyother shape. The waveguide may comprise material such as plastic orglass. The waveguide may comprise material used in an injection mold.

For example, in FIG. 5, the optical energy emitted from thephosphorescent material 502 is directed through the layer of waveguide506 to reach the photovoltaic cell 503. As described elsewhere herein,the phosphorescent material 502 may have absorbed optical energy at thefirst wavelength from a light source (not shown), such as in theconfiguration illustrated in FIG. 4A. The waveguide 506 may have arefractive index such as to allow for total internal reflection of theoptical wave at the second wavelength within the waveguide 506 untilsuch optical energy is transmitted to the photovoltaic cell 503. Thewaveguide may have a lower refractive index than any adjacent layer tothe waveguide. In some instances, the waveguide may be adjacent to thephosphorescent material from a first surface, and adjacent to thephotovoltaic cell from a second surface, wherein the first surface andthe second surface are substantially orthogonal. In some instances, thewaveguide may be adjacent to a plurality of layers of phosphorescentmaterial (e.g., interfacing different surfaces of the waveguide), andconfigured to direct waves received from the plurality of layers ofphosphorescent material to the photovoltaic cell.

FIG. 6 illustrates another photon battery assembly with waveguides. Aphoton battery assembly 600 can comprise a light source 601, aphosphorescent material 602, a photovoltaic cell 603, a first waveguide604, and a second waveguide 606. In some instances, the first waveguide604 may correspond to the waveguide 404 described with respect to FIG.4. In some instances, the second waveguide 606 may correspond to thewaveguide 506 described with respect to FIG. 5.

The photon battery assembly 600 may be constructed such that the firstwaveguide 604 is adjacent to the second waveguide 606, and the secondwaveguide is adjacent to the phosphorescent material 602. The firstwaveguide and the phosphorescent material may each be adjacent to twosurfaces of the second waveguide that are substantially parallel. Thefirst waveguide may be adjacent to the light source 601. The lightsource and the second waveguide may be adjacent to two surfaces of thefirst waveguide that are substantially orthogonal. The second waveguidemay be adjacent to the photovoltaic cell 603. The photovoltaic cell andthe phosphorescent material may be adjacent to two surface of the secondwaveguide that are substantially orthogonal. In some instances, thephotovoltaic cell and the light source may be substantially paralleland/or coplanar. The configuration of the photon battery assembly withwaveguides is not limited to FIG. 6.

In operation, the photon battery may be charged via the first waveguide604 which guides optical energy emitted by the light source 601 at thefirst wavelength to the phosphorescent material 602. The optical energyreceived from the light source may be substantially orthogonallyreflected (e.g., via a reflective surface) within the first waveguide topass through the second waveguide 606 (with minimal energy loss) foreven absorption across the phosphorescent material and subsequentexcitation. After a time delay, as described elsewhere herein, thephosphorescent material may emit optical energy at a second wavelength.Such emission may be isotropic (e.g., non-direction specific). Theemitted optical energy may be directed by the second waveguide, such asvia total internal reflection, to the photovoltaic cell for absorptionby the photovoltaic cell. Alternatively or in addition, the emittedoptical energy may be directed to the photovoltaic cell directly. Insome instances, the second waveguide may have a refractive index that islower than that of the first waveguide and that of the phosphorescentmaterial to allow for total internal reflection. As illustrated in FIG.6, the photon battery may be stacked in a similar configuration.

FIG. 7 shows a stack of a plurality of photon battery assemblies. Aphoton battery assembly can be connected to achieve different desiredvoltages, energy storage capacities, power densities, and/or otherbattery properties. For example, an energy storage system 700 maycomprise a stack of a first photon battery assembly, a second photonbattery assembly, a third photon battery assembly, a fourth photonbattery assembly, and so on, which are stacked vertically orhorizontally. Each photon battery assembly may comprise (or share) alight source, phosphorescent material, photovoltaic cell, firstwaveguide, and second waveguide, as described elsewhere herein. WhileFIG. 7 shows six photon battery assemblies stacked together, any numberof photon battery assemblies can be stacked together in anyconfiguration. For example, at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20,25, 30, 35, 40, 45, 50, 100, 200, or more photon battery assemblies canbe stacked together. While FIG. 7 shows a linear grid-like stack in thehorizontal and vertical directions, the assemblies can be stacked indifferent configurations, such as in concentric (or circular) stacks.

FIG. 8 shows an exploded view of another configuration for a photonbattery assembly stack with hollow core waveguides. A waveguide 806 maycomprise a hollow core. For example, the waveguide may be an opticalfiber or cable with a hollow core. Alternatively, the waveguide may havea cavity or trench with an opening. The waveguide may have a pluralityof cavities or trenches with a plurality of openings. The hollow core(or cavity or trench) may be filled by phosphorescent material 802 suchas to form filled cylindrical units. Alternatively, the hollow core maybe any shape (e.g., rectangular, triangular, hexagonal, non-polygonal,etc.). The cylindrical units may be linearly stacked, such as in groupsof 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 100, 200, or more units.The groups of linearly stacked cylindrical units may be sandwiched onopposing sides by light source panels 801. In some instances, a singlelight source panel may stretch along a length of a cylindrical unit.Alternatively, as shown in FIG. 8, a plurality of light source panelsmay be intermittently placed along the length of the single cylindricalunit. In some instances, groups of linearly stacked cylindrical unitsand the sandwiching light source panels may be stacked in alternatinglayers. Although this example shows four groups of six linearly stackedcylindrical units alternating with five light source panels for eachunit length of cylindrical unit, the stack may be in any configuration(e.g., 25 groups of 7 linearly stacked cylindrical units alternatingwith 26 light source panels). A photovoltaic cell 803 may be adjacent tothe end of the cylindrical units, substantially orthogonal to thelengths of the cylindrical units, and substantially orthogonal to thelight source panels. The photon battery assembly may resemble a cuboidshape, as illustrated in FIG. 8. The photon battery assembly is notlimited to the configuration illustrated in FIG. 8.

In some instances, the light source panel 801 may comprise a lightsource (e.g., LED) and a waveguide. The waveguide may correspond to thewaveguide 404 described with respect to FIG. 4 and configured to directoptical energy from the light source to different cylindrical units.FIG. 9 illustrates a partial cross-sectional side view of the photonbattery assembly stack of FIG. 8. The optical energy emitted by a lightsource 901 is directed by one or more reflective surfaces 905 in a firstwaveguide (e.g., in the light source panel 801) to the phosphorescentmaterial 902 in different cylindrical units. The optical energy may passthrough a second waveguide 906 (configured to direct optical energyemitted from the phosphorescent material to the photovoltaic cell (notshown)). The first waveguide may comprise increasingly larger reflectivesurfaces (e.g., 905) in the direction of the optical path of the opticalenergy emitted by the light source 901 such as to evenly distribute theoptical energy to the different cylindrical units (e.g., in the linearstack).

Each photon battery assembly can be configured as described in FIGS.1-9. Alternatively, different components of the photon battery assembly(e.g., light source, phosphorescent material, photovoltaic cell, firstwaveguide, second waveguide, coating, etc.) can be stacked in differentconfigurations (e.g., orders). A plurality of photon battery assembliescan be electrically connected in series, in parallel, or a combinationthereof. In some instances, there may be interconnects and/or otherelectrical components between each photon battery assembly. In someinstances, a controller can be electrically coupled to one or morephoton battery assemblies and be capable of managing the inflow and/oroutflow of power from each or a combination of the battery assemblies.

FIG. 10 illustrates a method of storing energy in a photon battery. Themethod can comprise, at a first operation 1001, emitting optical energyat a first wavelength (e.g., λ₁) from a light source. The optical energyat the first wavelength can be emitted from a light-emitting surface ofthe light source. The light source can be an artificial light source,such as a LED, laser, or lamp. The light source can be a natural lightsource. The light source can be powered by an electric power source,such as another energy storage device (e.g., battery, supercapacitors,capacitors, fuel cells, etc.) or another power supply (e.g., electricalgrid).

At a second operation 1002, a phosphorescent material that is adjacentto the light source can absorb the optical energy at the firstwavelength. The optical energy may be directed from the light source tothe phosphorescent material via a first waveguide. For example, thephosphorescent material can be adjacent to the light-emitting surface ofthe light source. In some instances, the first wavelength can be anultraviolet wavelength (e.g., 20-400 nm).

At a next operation 1003, after a time delay, the phosphorescentmaterial can emit optical energy at a second wavelength (e.g., λ₂). Insome instances, the first wavelength can be a visible wavelength (e.g.,400-700 nm). The second wavelength can be greater than the firstwavelength. That is, the optical energy at the first wavelength can beat a higher energy level than the optical energy at the secondwavelength. In some instances, the rate of absorption of the opticalenergy at the first wavelength by the phosphorescent material can befaster than the rate of emission of the optical energy at the secondwavelength by the phosphorescent material.

At a next operation 1004, a photovoltaic cell adjacent to thephosphorescent material can absorb the optical energy at the secondwavelength that is emitted by the phosphorescent material. The opticalenergy may be directed from the phosphorescent material to thephotovoltaic cell via a second waveguide. For example, a light-absorbingsurface of the photovoltaic cell can absorb the optical energy at thesecond wavelength. In some instances, the photovoltaic cell can betailored to absorb the wavelength or range of wavelengths that isemitted by the phosphorescent material. In some instances, thelight-absorbing surface of the photovoltaic cell can comprise one ormore depressions defined by corresponding protrusions to allow forincreased interfacial surface area between the phosphorescent materialand the photovoltaic cell.

At a next operation 1005, the photovoltaic cell can convert the absorbedoptical energy at the second wavelength and generate electrical power.In some instances, the electrical power generated by the photovoltaiccell can be used to power an electrical load that is electricallycoupled to the photovoltaic cell. The electrical load can be anelectronic device, such as a mobile phone, tablet, or computer. Theelectrical load can be a vehicle, such as a car, boat, airplane, ortrain. The electrical load can be a power grid. In some instances, atleast some of the electrical power generated by the photovoltaic cellcan be used to power the light source, such as when no electrical loadis connected to the photovoltaic cell. In some instances, at least someof the electrical power generated by the photovoltaic cell can be usedto charge a rechargeable battery (e.g., lithium ion battery), such aswhen no electrical load is connected to the photovoltaic cell. Therechargeable battery can in turn be used to power the light source.Beneficially, a photon battery assembly used in this method can be atleast in part self-sustaining and prevent loss of energy from the system(e.g., other than from inefficient conversion of energy).

FIG. 11 shows a computer control system. The present disclosure providescomputer control systems that are programmed to implement methods of thedisclosure. A computer system 1101 is programmed or otherwise configuredto regulate one or more circuitry in a photon battery assembly, inaccordance with some embodiments discussed herein. For example, thecomputer system 1101 can be a controller, a microcontroller, or amicroprocessor. In some cases, the computer system 1101 can be anelectronic device of a user or a computer system that is remotelylocated with respect to the electronic device. The electronic device canbe a mobile electronic device. The computer system 1101 can be capableof sensing the connection(s) of one or more electrical loads with aphoton battery assembly, the connection(s) of one or more rechargeablebatteries with a photon battery assembly, and/or the connection(s) of aphotovoltaic cell and a light source within a photon battery assembly.The computer system 1101 may be capable of managing the inflow and/oroutflow of power from each or a combination of photon battery assemblieselectrically connected in series or in parallel, and in some cases,individually or collectively electrically communicating with a powersource and/or an electrical load. The computer system 1101 may becapable of computing a rate of discharge of power from the photonbattery and/or a rate of consumption of power by an electrical load. Forexample, the computer system may be based on such computation, determinewhether and how to direct power discharged from a photovoltaic cell to alight source, an external battery (e.g., lithium ion battery), and/or anelectrical load. The computer system may be capable of adjusting orregulating a voltage or current of power input and/or power output ofthe photon battery. The computer system 1101 may be capable of adjustingand/or regulating different component settings. For example, thecomputer system may be capable of adjusting or regulating a brightness,intensity, color (e.g., wavelength, frequency, etc.), pulsation period,or other optical characteristics of a light emitted by a light source inthe photon battery assembly. For example, the computer system may beconfigured to adjust a light emission setting from a light sourcedepending on the type of phosphorescent material used in the photonbattery.

For example, the computer system 1101 can be capable of regulatingdifferent charging and/or discharging mechanisms of a photon batteryassembly. The computer system may turn on an electrical connectionbetween a light source and a power supply to start charging the photonbattery assembly. The computer system may turn off an electricalconnection between the light source and the power supply to stopcharging the photon battery assembly. The computer system may turn on oroff an electrical connection between a photovoltaic cell and anelectrical load. In some instances, the computer system may be capableof detecting a charge level (or percentage) of the photon batteryassembly. The computer system may be capable of determining when theassembly is completely charged (or nearly completely charged) ordischarged (or nearly completely discharged). In some instances, thecomputer system may be capable of maintaining a certain range of chargelevel (e.g., 5%˜95%, 10%˜90%, etc.) of the photon battery assembly, suchas to maintain and/or increase the life of the photon battery assembly,which complete charge or complete discharge can detrimentally shorten.

The computer system 1101 includes a central processing unit (CPU, also“processor” and “computer processor” herein) 1105, which can be a singlecore or multi core processor, or a plurality of processors for parallelprocessing. The computer system 1101 also includes memory or memorylocation 1110 (e.g., random-access memory, read-only memory, flashmemory), electronic storage unit 1115 (e.g., hard disk), communicationinterface 1120 (e.g., network adapter) for communicating with one ormore other systems, and peripheral devices 1125, such as cache, othermemory, data storage and/or electronic display adapters. The memory1110, storage unit 1115, interface 1120 and peripheral devices 1125 arein communication with the CPU 1105 through a communication bus (solidlines), such as a motherboard. The storage unit 1115 can be a datastorage unit (or data repository) for storing data. The computer system1101 can be operatively coupled to a computer network (“network”) 1130with the aid of the communication interface 1120. The network 1130 canbe the Internet, an internet and/or extranet, or an intranet and/orextranet that is in communication with the Internet. The network 1130 insome cases is a telecommunication and/or data network. The network 1130can include one or more computer servers, which can enable distributedcomputing, such as cloud computing. The network 1130, in some cases withthe aid of the computer system 1101, can implement a peer-to-peernetwork, which may enable devices coupled to the computer system 1101 tobehave as a client or a server.

The CPU 1105 can execute a sequence of machine-readable instructions,which can be embodied in a program or software. The instructions may bestored in a memory location, such as the memory 1110. The instructionscan be directed to the CPU 1105, which can subsequently program orotherwise configure the CPU 1105 to implement methods of the presentdisclosure. Examples of operations performed by the CPU 1105 can includefetch, decode, execute, and writeback.

The CPU 1105 can be part of a circuit, such as an integrated circuit.One or more other components of the system 1101 can be included in thecircuit. In some cases, the circuit is an application specificintegrated circuit (ASIC).

The storage unit 1115 can store files, such as drivers, libraries andsaved programs. The storage unit 1115 can store user data, e.g., userpreferences and user programs. The computer system 1101 in some casescan include one or more additional data storage units that are externalto the computer system 1101, such as located on a remote server that isin communication with the computer system 1101 through an intranet orthe Internet.

The computer system 1101 can communicate with one or more local and/orremote computer systems through the network 1130. For example, thecomputer system 1101 can communicate with all local energy storagesystems in the network 1130. In another example, the computer system1101 can communicate with all energy storage systems within a singleassembly, within a single housing, and/or within a single stack ofassemblies. In other examples, the computer system 1101 can communicatewith a remote computer system of a user. Examples of remote computersystems include personal computers (e.g., portable PC), slate or tabletPC's (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, Smart phones(e.g., Apple® iPhone, Android-enabled device, Blackberry®), or personaldigital assistants. The user can access the computer system 1101 via thenetwork 1130.

Methods as described herein can be implemented by way of machine (e.g.,computer processor) executable code stored on an electronic storagelocation of the computer system 1101, such as, for example, on thememory 1110 or electronic storage unit 1115. The machine executable ormachine readable code can be provided in the form of software. Duringuse, the code can be executed by the processor 1105. In some cases, thecode can be retrieved from the storage unit 1115 and stored on thememory 1110 for ready access by the processor 1105. In some situations,the electronic storage unit 1115 can be precluded, andmachine-executable instructions are stored on memory 1110.

The code can be pre-compiled and configured for use with a machinehaving a processor adapted to execute the code, or can be compiledduring runtime. The code can be supplied in a programming language thatcan be selected to enable the code to execute in a pre-compiled oras-compiled fashion.

Aspects of the systems and methods provided herein, such as the computersystem 1101, can be embodied in programming. Various aspects of thetechnology may be thought of as “products” or “articles of manufacture”typically in the form of machine (or processor) executable code and/orassociated data that is carried on or embodied in a type of machinereadable medium. Machine-executable code can be stored on an electronicstorage unit, such as memory (e.g., read-only memory, random-accessmemory, flash memory) or a hard disk. “Storage” type media can includeany or all of the tangible memory of the computers, processors or thelike, or associated modules thereof, such as various semiconductormemories, tape drives, disk drives and the like, which may providenon-transitory storage at any time for the software programming. All orportions of the software may at times be communicated through theInternet or various other telecommunication networks. Suchcommunications, for example, may enable loading of the software from onecomputer or processor into another, for example, from a managementserver or host computer into the computer platform of an applicationserver. Thus, another type of media that may bear the software elementsincludes optical, electrical and electromagnetic waves, such as usedacross physical interfaces between local devices, through wired andoptical landline networks and over various air-links. The physicalelements that carry such waves, such as wired or wireless links, opticallinks or the like, also may be considered as media bearing the software.As used herein, unless restricted to non-transitory, tangible “storage”media, terms such as computer or machine “readable medium” refer to anymedium that participates in providing instructions to a processor forexecution.

Hence, a machine readable medium, such as computer-executable code, maytake many forms, including but not limited to, a tangible storagemedium, a carrier wave medium or physical transmission medium.Non-volatile storage media include, for example, optical or magneticdisks, such as any of the storage devices in any computer(s) or thelike, such as may be used to implement the databases, etc. shown in thedrawings. Volatile storage media include dynamic memory, such as mainmemory of such a computer platform. Tangible transmission media includecoaxial cables; copper wire and fiber optics, including the wires thatcomprise a bus within a computer system. Carrier-wave transmission mediamay take the form of electric or electromagnetic signals, or acoustic orlight waves such as those generated during radio frequency (RF) andinfrared (IR) data communications. Common forms of computer-readablemedia therefore include for example: a floppy disk, a flexible disk,hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD orDVD-ROM, any other optical medium, punch cards paper tape, any otherphysical storage medium with patterns of holes, a RAM, a ROM, a PROM andEPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wavetransporting data or instructions, cables or links transporting such acarrier wave, or any other medium from which a computer may readprogramming code and/or data. Many of these forms of computer readablemedia may be involved in carrying one or more sequences of one or moreinstructions to a processor for execution.

The computer system 1101 can include or be in communication with anelectronic display 1135 that comprises a user interface (UI) 1140 forproviding, for example, user control options (e.g., start or terminatecharging, start or stop powering an electrical load, route power back toself-charging, etc.). Examples of UI's include, without limitation, agraphical user interface (GUI) and web-based user interface.

Methods and systems of the present disclosure can be implemented by wayof one or more algorithms. An algorithm can be implemented by way ofsoftware upon execution by the central processing unit 1105. Thealgorithm can, for example, change circuitry of a photon batteryassembly or a stack of photon battery assemblies based on, for example,sensing the connection(s) of one or more electrical loads with a photonbattery assembly, the connection(s) of one or more rechargeablebatteries with a photon battery assembly, and/or the connection(s) of aphotovoltaic cell and a light source within a photon battery assembly.The algorithm may be capable of managing the inflow and/or outflow ofpower from each or a combination of photon battery assemblieselectrically connected in series or in parallel, and in some cases,individually or collectively electrically communicating with a powersource and/or an electrical load.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. It is not intendedthat the invention be limited by the specific examples provided withinthe specification. While the invention has been described with referenceto the aforementioned specification, the descriptions and illustrationsof the embodiments herein are not meant to be construed in a limitingsense. Numerous variations, changes, and substitutions will now occur tothose skilled in the art without departing from the invention.Furthermore, it shall be understood that all aspects of the inventionare not limited to the specific depictions, configurations or relativeproportions set forth herein which depend upon a variety of conditionsand variables. It should be understood that various alternatives to theembodiments of the invention described herein may be employed inpracticing the invention. It is therefore contemplated that theinvention shall also cover any such alternatives, modifications,variations or equivalents. It is intended that the following claimsdefine the scope of the invention and that methods and structures withinthe scope of these claims and their equivalents be covered thereby.

What is claimed is:
 1. A system for storing energy, comprising: a lightsource configured to emit optical energy at a first wavelength from asurface of said light source; a phosphorescent material configured to(i) absorb said optical energy at said first wavelength, and (ii) at arate slower than a rate of absorption, emit optical energy at a secondwavelength, wherein said second wavelength is greater than said firstwavelength, wherein said phosphorescent material comprises grains havinga particle size of less than about 5 micrometers; a photovoltaic celladjacent to said phosphorescent material, wherein said photovoltaic cellis configured to (i) absorb optical energy at said second wavelength,and (ii) generate electrical power from optical energy; and a waveguideadjacent to said phosphorescent material, wherein said waveguide isconfigured to (i) direct said optical energy at said first wavelengthfrom said light source to said phosphorescent material or (ii) directsaid optical energy at said second wavelength from said phosphorescentmaterial to said photovoltaic cell.
 2. The system of claim 1, whereinsaid waveguide is configured to direct said optical energy at said firstwavelength from said light source to said phosphorescent material andwherein said system comprises a second waveguide configured to directsaid optical energy at said second wavelength from said phosphorescentmaterial to said photovoltaic cell.
 3. The system of claim 2, whereinsaid second waveguide and said phosphorescent material are concentric.4. The system of claim 1, wherein said waveguide is configured to directsaid optical energy at said first wavelength from said light source tosaid phosphorescent material, and wherein said waveguide is adjacent tosaid light source.
 5. The system of claim 1, wherein said waveguide isconfigured to direct said optical energy at said second wavelength fromsaid phosphorescent material to said photovoltaic cell, and wherein saidwaveguide is adjacent to said photovoltaic cell.
 6. The system of claim1, wherein said waveguide comprises one or more reflective surfaces,wherein said one or more reflective surfaces are configured to (i)direct said optical energy at said first wavelength from said lightsource to said phosphorescent material or (ii) direct said opticalenergy at said second wavelength from said phosphorescent material tosaid photovoltaic cell.
 7. The system of claim 4, wherein said waveguidecomprises a plurality of reflective surfaces having increasingly largereflective surfaces along an optical path within said waveguide, suchthat a first set of waves from said light source are configured to bereflected at a first reflective surface of said plurality of reflectivesurfaces for excitation of a first volume of phosphorescent material,and a second set of waves from said light source are configured to bereflected at a second reflective surface of said plurality of reflectivesurfaces for excitation of a second volume of phosphorescent material,wherein said second volume of phosphorescent material is disposed at agreater distance from said light source than said first volume ofphosphorescent material.
 8. The system of claim 1, wherein arechargeable battery is electrically coupled to said light source andsaid photovoltaic cell, and wherein at least part of said electricalpower generated by said photovoltaic cell charges said rechargeablebattery, and wherein at least part of electrical power discharged bysaid rechargeable battery powers said light source.
 9. The system ofclaim 1, wherein said phosphorescent material comprises one or morematerials selected from the group consisting of: strontium aluminate,europium, and dysprosium.
 10. The system of claim 1, wherein saidphosphorescent material comprises grains having a particle size of lessthan about 20 nanometers.
 11. The system of claim 1, wherein said lightsource is adjacent to and in contact with said waveguide.
 12. The systemof claim 1, wherein said light source is located remote from saidwaveguide and said phosphorescent material, wherein said light source isin optical communication with said waveguide.
 13. The system of claim 1,further comprising a coating on said waveguide, wherein said coating isin optical communication with said waveguide and said phosphorescentmaterial, wherein said coating comprises an optical filter.
 14. Thesystem of claim 13, wherein said optical filter is a dichroic element.15. The system of claim 13, wherein said optical filter is configured totransmit waves having said first wavelength from said waveguide to saidphosphorescent material and reflect waves having said second wavelengthfrom said phosphorescent material back to said phosphorescent material.16. The system of claim 13, wherein said coating is in contact with saidwaveguide and said phosphorescent material.
 17. A system for storingenergy, comprising: a light source configured to emit optical energy ata first wavelength from a surface of said light source; a phosphorescentmaterial configured to (i) absorb said optical energy at said firstwavelength, and (ii) at a rate slower than a rate of absorption, emitoptical energy at a second wavelength, wherein said second wavelength isgreater than said first wavelength; a photovoltaic cell adjacent to saidphosphorescent material, wherein said photovoltaic cell is configured to(i) absorb optical energy at said second wavelength, and (ii) generateelectrical power from optical energy; a waveguide adjacent to saidphosphorescent material, wherein said waveguide is configured to (i)direct said optical energy at said first wavelength from said lightsource to said phosphorescent material or (ii) direct said opticalenergy at said second wavelength from said phosphorescent material tosaid photovoltaic cell; and a coating on said waveguide, wherein saidcoating is in optical communication with said waveguide and saidphosphorescent material, wherein said coating comprises an opticalfilter.
 18. The system of claim 17, wherein said optical filter is adichroic element.
 19. The system of claim 17, wherein said opticalfilter is configured to transmit waves having said first wavelength fromsaid waveguide to said phosphorescent material and reflect waves havingsaid second wavelength from said phosphorescent material back to saidphosphorescent material.
 20. The system of claim 17, wherein saidcoating is in contact with said waveguide and said phosphorescentmaterial.